On the Cover: Looking from Earth, with eyes that see only in a limited spectrum, humans have not been able to determine if deposits of water lie hidden on the Moon. This compound, so abundant on our planet, once seemed absent from Earth's satellite. But the Lunar Prospector spacecraft, carrying instruments that see differently than our eyes, has found evidence of water ice in places near the poles that never feel the Sun's light. In this image of the north pole, compiled from neutron spectrometer data, the places most likely to hold water ice are dark blue and magenta; orange-red marks the places least likely to have it.NASA Ames Research Center